1. Field of the Invention.
The present invention is in the field of methods of bonding a polymeric material to a web. More particularly, this invention is in the field of bonding a polymer to fibrous substrate.
2. Description of the Prior Art.
Composite materials formed by the adhesion of a polymer to a web, such as, e.g., fabric webs, are well-known in the art. Examples of such composites include raincoats, rubber on cotton; tires, rubber on glass or steel; and wet-strength paper, urea-formaldehyde on cellulose.
Methods of applying the polymer to the web include dipping the web into a solution or suspension of the polymer, and calendering the web with the polymer. When a polymer and the web are co-calendered, it is desireable to have a composite in which the adjacent layers adhere to other layers. This can be measured as peel strength in grams (g) per centimeter (cm) necessary to separate adjacent layers of a 2.54-cm-wide strip.
Attempts to produce composites with improved peel strengths have included, e.g., increased pressure and temperature of the calender rolls, and pre-heat-treating the fabric web by infra-red or other heat application. Such treatments have resulted only in incremental improvements in peel strength.